Question

# When a plastic rod and a metal rod removed from the freezer (same initial temperature) are...

1. When a plastic rod and a metal rod removed from the freezer (same initial temperature) are touched, metal rod is felt cooler than the plastic rod. Why?

2. Does heat flow depend on temperature of the two substances or temperature difference between the substances?

3. Which can be easily heated and cooled? (a) Substance of specific heat capacity = 300 J/kg. C, (b) substance of specific heat capacity = 900 J/kg. C

1.

When you touch metal, its high thermal conductivity allows heat to flow out of your finger and into the metal more quickly than plastic ( which have a low thermal conductivity ). So it pulls more heat away from your finger, so the temperature of your finger changes faster, so it feels colder.

2.

Yes. Heat flow increases with increase in heat flow depend on temperature of the two substances

3.

High Specific Heat means that it takes more energy to raise (or lower) its temperature.

Answer is Substance of specific heat capacity = 300 J/kg. C can be cooled easily

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